Clerget 7Z
# Clerget 7Z

The Clerget 7Z was a seven-cylinder rotary aircraft engine of the World War I era designed by Pierre Clerget. First appearing in 1911 it was nominally rated at 80 horsepower (60 kW). 347 examples were jointly built in Britain by Gordon Watney & Co Ltd of Weybridge and Gwynnes Limited of Hammersmith.

## Applications

* Avro 504
* Beardmore W.B.III
* Bristol S.S.A.
* Caudron G.4
* Mosca-Bystritsky MBbis
* Royal Aircraft Factory B.E.8a
* Royal Aircraft Factory S.E.2
* Royal Aircraft Factory S.E.4
* Sopwith Pup
* Weymann W-1

## Specifications (Clerget 7Z)

Data from Lumsden and Gunston.

### General characteristics

* Type: Seven-cylinder air-cooled rotary engine
* Bore: 120 mm (4.72 in)
* Stroke: 150 mm (5.91 in)
* Displacement: 11.88 L (724.96 cu in)
* Diameter: 914 mm (35.98 in)
* Dry weight: 106 kg (234 lb)

### Components

* Valvetrain: 1 each overhead inlet and exhaust valves operated by pushrods and rockers
* Fuel system: Bloctube carburettor
* Fuel type: Gasoline with Castor oil lubricant
* Oil system: Castor oil mixed with fuel
* Cooling system: Air-cooled

### Performance

* Power output: 70.84 kW (95 hp) at 1,300 rpm (maximum power)
* Specific power: 0.1314 hp/cu in (5.98 kW/L)
* Compression ratio: 4.3:1
* Specific fuel consumption: 0.564 L/kW/hour(0.74 pt/hp/hour)
* Oil consumption: 0.0762 L/kW/hour (0.1 pt/hp/hour)
* Power-to-weight ratio: 0.67 kW/kg (0.406 hp/lb)
